BimmerFest BMW Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter #1
I have a leak coming from the small bolt on the passenger side close to the transmission..see images. It's definitely engine oil.

I noticed a bit of oil on the aluminum engine skid plate when I popped the hood. Took the belly pan off, cleaned everything up and determined the oil is coming out of this bolt. I tried tightening and it turned 1/4 turn, I did not want to overtighten it, but it's still dripping very slightly. Any ideas what this is. It's all clean everywhere else.

2008 528xi with 74K miles
 

Attachments

·
Registered
Joined
·
5,550 Posts
A leak on this side is usually the valve cover gasket. That bolt on the bottom doesn't seal any oil lines.
 

·
Registered
Joined
·
11 Posts
Discussion Starter #3
The strange thing is that I looked at the valve cover gasket and it's clean... unless it's all the way back up against the firewall. Also, there are no signs of oil up above this bolt.
 

·
Registered
Joined
·
5,550 Posts
As you can see it on the image below, that is a "dry" area. The closest gasket is the oil pan gasket but that's below this bolt. The other seal is the rear main seal (around the crankshaft) but that would show up at the very bottom of the engine.

 

·
Registered
Joined
·
252 Posts
That's the exact spot I had an oil leak last year on my 2008 528xi at ~155,000 miles. It ended up being the rear main seal. I had it repaired at the dealer, it cost about $1400.

Scott
 

·
Registered
Joined
·
11 Posts
Discussion Starter #8
As you can see it on the image below, that is a "dry" area. The closest gasket is the oil pan gasket but that's below this bolt. The other seal is the rear main seal (around the crankshaft) but that would show up at the very bottom of the engine.

acoste - is the bolt I'm leaking out of the one I circled in red on your image?
 

Attachments

·
Registered
Joined
·
5,550 Posts
acoste - is the bolt I'm leaking out of the one I circled in red on your image?
Yes. It is possible that the rear main seal is leaking a bit (the black ring with ~3 inches of diameter) and since the engine is tilted to the right in the car, the oil might flow towards that bolt on the edge of the oil pan gasket.

I don't think it's severe since I can't see any oil on your picture near that 1 inch hole on the transmission bell housing (where you can see the flywheel).

If it's the rear main seal and you don't experience any massive oil loss, just leave it for now until the transmission needs any service.
 

·
Registered
2006 530xi 6 MT
Joined
·
4,549 Posts
If you think that's the leak, I agree with acoste. Unless you are having to add oil in between oil changes or it is making a mess in the garage floor, I'd leave it alone for now.
 

·
Registered
Joined
·
11 Posts
Discussion Starter #12 (Edited)
I jacked her up again since it has been a week since I originally discovered the leak to look a little deeper. There are absolutely no traces of oil coming down from the valve cover gasket. I removed the filters and the plastic covers up against the firewall for better visibility.

I looked inside the transmission bell housing and there are no signs of oil in that area.

The oil pan gasket is also dry all the way around as far as I can see. The only way I see this leak happening is if the oil pan has a leak around one of the bolt's behind my "wet" bolt and it's dripping down and accumulating on it.

Is this a possibility or is rear main seal more probable?


I added a few updated pictures. The oil is still visible only around this one bolt.

Thanks for all the input!
 

Attachments

·
Registered
Joined
·
5,550 Posts
I still think it comes from above :p
and flows down on that curved edge. Note that this is very little amount of oil.
 

·
Registered
Joined
·
294 Posts
I still think it comes from above :p
and flows down on that curved edge. Note that this is very little amount of oil.
I agree; I can't imagine the rear main seal leaking to that exact point. Likely that it's the valve cover gasket or even cylinder head gasket. It could also be leaking from the front and slowing finding its way to the rear of the engine.
 

·
Registered
Joined
·
252 Posts
Same debate I went through. I don't know how many times I sprayed carb cleaner to clean up the oil, then it always came back to the same spot. I even had an engine support specced as I was going to replace the oil pan gasket myself. When I finally took it to the dealer, he said it was either the rear main seal or the block seal. These engines have a two part block, the seam is 2-3" up from the oil pan gasket. He said they wouldn't know which it was until the pulled the transmission. The rear seal quote (which it was) was $1400, the quote for the block seal was so much that a replacement engine was cheaper. Fortunately it was the rear main seal.
 
1 - 15 of 15 Posts
Top